The lighting unit can be applied variously to a backlight unit applied to a flat plate display, an interior lamp used in an indoor environment, a headlight, a fog light, a retraction light, a car-width light, a number light, a tail light, a brake light, turn signal light, emergency flashing light which are installed outside a vehicle, an indoor lighting installed inside a vehicle, or the like. Most of these lighting are mostly approaches in terms of brightness of a surface light source by applying a member such as a light guide plate that efficiently transmits light.
In a case of vehicle lighting, LEDs, which realize high optical efficiency, recently are being developed as a light source, and the use of LED packages as a light source is becoming more frequent in a case of vehicle lighting in a form of a surface lighting. However, in a case where the LED package is used as a light source, it is inevitably necessary to increase the number of optical elements that are responsible for the light emitting surface in case of where high light quantity is required or for the surface emitting and there are many problems in implementation of circuit between elements due to a cost aspect, the problem of heat dissipation, a curved portion of the vehicle, a narrow space, or the like and thus there is a fatal drawback that leads to high cost and low efficiency. Particularly, in a case of vehicle lighting disposed on in a limited space, many various designs are required, and in recent years, there has been an increasing demand for realizing three-dimensional light (3D) in light of a specific shape.
In addition, there is a growing need for a structure that can increase the degree of freedom of design and such attention is being extended to lighting that does not limit the light emitting surface to one direction.